Journal article
Impact ionization dynamics in silicon by MV/cm THz fields
Department of Photonics Engineering, Technical University of Denmark1
Diode Lasers and LED Systems, Department of Photonics Engineering, Technical University of Denmark2
Ultrafast Infrared and Terahertz Science, Department of Photonics Engineering, Technical University of Denmark3
Kyoto University4
We investigate the dynamics of the impact ionization (IMI) process in silicon in extremely high fields in the MV/cm range and at low initial carrier concentrations; conditions that are not accessible with conventional transport measurements. We use ultrafast measurements with high-intensity terahertz pulses to show that IMI is significantly more efficient at lower than at higher initial carrier densities.
Specifically, in the case of silicon with an intrinsic carrier concentration (∼1010 cm−3), the carrier multiplication process can generate more than 108 electrons from just a single free electron. The photoexcited carrier density dependence of the IMI rate shows that with decreasing initial carrier density the rate increases and approaches the fundamental Okuto limit imposed by energy conservation.
Language: | English |
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Publisher: | IOP Publishing |
Year: | 2017 |
Pages: | 123018 |
ISSN: | 13672630 |
Types: | Journal article |
DOI: | 10.1088/1367-2630/aa936b |
ORCIDs: | Jepsen, Peter Uhd and 0000-0002-2597-7032 |
Physics Q QC1-999 Science impact ionization silicon terahertz ultrafast dynamics